Six tactile printable token STL designs with validation

Design six original tactile identification tokens as printable STL assets. Each has a 24 by 24 millimetre base, flat bottom and a distinct raised geometric symbol: parallel bars, concentric squares, cross, zigzag, dots, spiral-like path. Each token must be one closed connected solid, not overlapping disconnected meshes. Deliver six STL files, editable generation source, an SVG contact sheet and a dependency-free mesh validator. Validate undirected edge incidence of exactly two faces, connectedness, finite coordinates, bounding boxes and consistently oriented positive volume. Report dimensions, triangle counts and volume for every token; choose simple robust manufacturable geometry. These are adult maker prototypes; no certification, accessibility efficacy claim or physical print test. Deliver English materials, original content and offline reproducible checks. The artifact is the product; no web application or external service. Make reasonable reversible design choices independently.

Advance the delivered Touchmarks kit with a faithful fabrication preview while preserving the six independently validated STL meshes byte-for-byte. Independent triangle analysis confirms each is a closed, connected, oriented 24x24x3.5 mm solid; the base is 2 mm and relief 1.5 mm. Keep all STL geometry and bytes unchanged. Their SHA-256 values are: concentric-squares.stl a1048261e11eaa71619ba5fdf28a31880f5242d52ae53779e03933b019890709; cross.stl 982f59d94ed47ddc9a776137da7fd3b02245dcd536581a597562f1ae212aef18; dots.stl d9c7e27582d522c3a627a7be8861617526b5ba61cc1ebeb597648730472f869a; parallel-bars.stl d0c068f3a029199f718eb4995ffa0191f113620aae6c15f1525f54abdbef2157; spiral.stl 8d47761911f76ee384fdbcd4da116f29317836641b6d352dc8b88bd661ef8b31; zigzag.stl c9202993188110de76d73487f5b87fa13b10a4bb21cc840299fc7627071cc2ee. Replace the conceptual contact-sheet.svg with six actual top views derived from delivered STL triangles, at a clearly documented consistent scale and orientation. The current drawings rotate the bars, distort square widths and the cross, draw dots as rings, and draw a different spiral that escapes its tile. The new preview must encode the actual filled raised regions from the mesh and keep every tile, label and outline within a printable page. Add a geometry comparison between the top-view raised footprints and the STL-derived footprints; reject a displaced tile, a removed or added raised cell, and an out-of-page drawing in disposable tests. Do not merely count shapes or repeat the mesh generation formula to claim agreement. Fix validate_mesh.check() returning dimensions.z=4.5 although its own measured bounds, report and mesh correctly show3.5. Return actual measured dimensions and test the returned result, without changing the accepted geometry. Clarify design-spec feature_width=2.0 as the applicable nominal stroke width or minimum design target rather than claiming every feature has width2: the cross arms are4mm and dots3mm diameter. Record actual shape-specific values and any grid discretization. Preserve working manifold/volume checks, update hashes and concise reproducible verification. Rebuild in two fresh directories and demonstrate all six supplied STL hashes remain identical. No physical printing or tactile-usability claim.